Research is conducted on flat displays having a large screen for use as displays for high definition television. CRTs generally in use as display devices are most excellent in respect of the quality of images since a high-speed electron beam is projected on phosphors for excitation. However, high definition television receivers of 40 inches or larger comprising such a display device exceed 170 kg in weight and 850 mm in depth and are not suited to household use.
Accordingly, U.S. Pat. No. 4,719,388 or Unexamined Japanese Patent Publication SHO 61-242489 discloses a flat display of the electron beam type which comprises linear filament cathodes -serving as electron beam emitters and in which the high-speed electron beams derived by XY matrix electrodes are adapted impinge on specified addresses on a fluorescent screen.
FIG. 16 shows the construction of the flat display disclosed in the U.S. patent. The display comprises a front panel 10 having a fluorescent screen on its rear surface, a rear panel 16 having a back electrode 32 on its inner surface, linear filament cathodes 14 and an address electrode plate 12 arranged in a flat space defined by the two panels, and a gridlike accelerating electrode 42 disposed between and in parallel to the filament cathodes 14 and the address electrode plate 12. The address electrode plate 12 comprises first address electrodes 26 formed on one surface of a substrate and extending in one direction of an XY matrix, and second address electrodes 28 formed on the other surface of the substrate 25 and extending in the other direction of the XY matrix, i.e. in a direction perpendicular to the address electrodes 26. The address electrode plate 12 is formed with apertures 24 at the respective intersections. When a positive voltage is applied to selected two electrodes 26, 28 at the same time, an electron beam is drawn through the aperture 24 positioned at the intersection of these electrodes to impinge on the specified address of the fluorescent screen on the front panel 10 to which a high voltage is applied, thereby causing luminescence.
This device operates on basically the same principle as the CRT and therefore gives images of higher quality than flat displays of other types, such as plasma display panel (PDP) type, liquid crystal display (LCD) type, and vacuum fluorescent display (VFD) type.
In the case of the flat display of the electron beam type, the interior of the display is maintained in a vacuum of 10.sup.-6 torr, so that the atmospheric pressure exerts a great compressive force on the front and rear panels and is likely to cause implosion. If small-sized, the display can be given the required pressure resistance by increasing the thickness of the glass panels, whereas with the large display of the construction shown in FIG. 16, the increase in the thickness of the panels entails the problem of a greatly increased weight.